Grenade, a small time-fuze bomb. Some are designed to be thrown by hand. The rifle grenade is launched by firing a blank cartridge in a rifle with a special adapter. The grenade launcher is a largebore weapon that fires an explosive cartridge that, in turn, launches a grenade. United States armed forces are equipped with a fully automatic grenade launcher called a 40-mm machine gun.
Some grenades contain tear gas, incendiaries, or smoke generators. Those that contain explosives may be of the fragmentation type (for use against troops) or of the concussion type (for use against armored vehicles and light fortifications).
Grenades were first used in the 1400's and were especially important during 1600–1750. Soldiers who threw them were called grenadiers. Guns that fired grenades were first developed in the 1500's. The use of grenades died out in the early 19th century, but was revived in the Russo-Japanese War (1904–05). The Soviet Union introduced the automatic—grenade launcher in the 1970's; the United States introduced one in 1990.